From b68faad19e60c00ae354fe41a8e2e03dfc799cb8 Mon Sep 17 00:00:00 2001
From: Clemens Ladisch <clemens@ladisch.de>
Date: Sun, 16 Feb 2014 17:11:10 +0100
Subject: ALSA: usb-audio: work around KEF X300A firmware bug

commit 624aef494f86ed0c58056361c06347ad62b26806 upstream.

When the driver tries to access Function Unit 10, the KEF X300A
speakers' firmware apparently locks up, making even PCM streaming
impossible.  Work around this by ignoring this FU.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/sound/usb/mixer_maps.c b/sound/usb/mixer_maps.c
index cc2dd1f..0339d46 100644
--- a/sound/usb/mixer_maps.c
+++ b/sound/usb/mixer_maps.c
@@ -322,6 +322,11 @@ static struct usbmix_name_map hercules_usb51_map[] = {
 	{ 0 }				/* terminator */
 };
 
+static const struct usbmix_name_map kef_x300a_map[] = {
+	{ 10, NULL }, /* firmware locks up (?) when we try to access this FU */
+	{ 0 }
+};
+
 /*
  * Control map entries
  */
@@ -409,6 +414,10 @@ static struct usbmix_ctl_map usbmix_ctl_maps[] = {
 		.id = USB_ID(0x200c, 0x1018),
 		.map = ebox44_map,
 	},
+	{
+		.id = USB_ID(0x27ac, 0x1000),
+		.map = kef_x300a_map,
+	},
 	{ 0 } /* terminator */
 };
 
-- 
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